The Trun Gorge is a canonical gorge on the Erma River in western Bulgaria, in the easternmost part of Mount Rui, in the Municipality of Trun, Pernik District, about 3.5 km north of the town of Trun and 85 km from Sofia.
The Trun Gorge is associated with a local legend about the impossible love between two lovers – a rich girl and a poor young man. A mother’s oath cursed them, and they became two rocks on either side of the river Erma, so that they were always close to each other, but never together. The waters of the river were nourished by the tears of the two separated.